Cardiac Anesthesia Update

Charles E. Smith, MD

Professor, CWRU School of Medicine

Director, CT Anesthesia

MetroHealth Medical Center

Objectives

1. ASE guidelines- IOTEE

2. ACC/AHA guidelines- Valves

3. Diabetes + hyperglycemia

4. Neurocognitive dysfunction

5. Transfusion

ASE/SCA Guidelines- TEE

• Accelerated growth of IOTEE by anesthesia

• Complexity of US technology

• Conduct of exam

• Interpretation of results

Mathews JP et al: ASE / SCA Recommendations and Guidelines for CQI in Perioperative Echo. JASE + Anesth Analg 2006.

Training + Credentialing

• 2 levels of training: basic + advanced– Basic: within usual practice of anesthesia

– ventricular fct, gross valve lesions

– Advanced: full diagnostic potential of echo

• ASE /SCA/NBE:– Testamur status: exam

– Board certified: 1 yr TEE/ CT fellowship [vs alternate training, 2-4 yr, 300 exams]

• Credentialing: hospital-specific process

Mathews JP et al: JASE + Anesth Analg 2006.

Standard TEE Exam: Guidelines

• Comprehensive: 20 cross-sectional views

– UE level: Asc aorta, MPA, L+R atria, AV+PV

– ME level: L+R atria, L+R ventricles, MV+TV

– TG: L+R ventricles

– Thoracic Aorta: Desc + distal archMathews JP et al: ASE / SCA Recommendations and Guidelines for CQI in Perioperative Echo. JASE + Anesth Analg 2006.

Transgastric view: L+R ventricles

ME views: L+R atria, L+R ventricles, MV+TV

UE views: Asc aorta, MPA, L+R atria, AV+PV, pulm veins

Thoracic Aorta: prox asc aorta, distal arch, descending

ACC/AHA Guidelines• Review of literature by experts• Grade evidence: Level A →C [RCT→opinion]• Recommendations: • Class I: beneficial• Class IIa: generally in favor• Class IIb: less well established• Class III: not useful, potentially harmful?

AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS

Valvular Heart Disease

• Decision to repair/replace valve should be made before surgery

• IOTEE should be used to confirm dx, evaluate repair + evaluate new findings (e.g., moderate AS in setting of CABG, moderate AI if ↓ EF or ↑ LVEDD, aortic root reconstruction if dilated > 5 cm)

AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS

IOTEE Indications

• Class I: valve repair, valve replacement- stentless / autograft (Ross), valve surgery in setting of endocarditis – Level of evidence= B

• Class IIa: all valve surgeries – Level of evidence =C

AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS

Aortic Stenosis

• Check annulus size

• Verify size of aortic root (mismatch? aneurysmal?)

• After bypass: problems w prosthesis: immobility, leaks

AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS

Severe Aortic Stenosis

5.7 m/s

2.0 cm

1.3 m/s 2.0 2 1.3AVA = 3.14 ( ------) X ------ = 0.72 cm2

2 5.7

Severe Aortic RegurgitationT 1/2 = 84 msT 1/2 = 84 ms

Vena Contracta = 11 mmVena Contracta = 11 mm

Mitral Regurgitation

AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS

Functional vs structural

After bypass:

Residual MR, MS, SAM

Leaks

Immobility of prosthesis

Severe Mitral Regurgitation

PISA ROAPISA ROA

rrnn=1.1cm=1.1cm

vvnn=59 cm=59 cm

vvpp=450 cm=450 cm

= 2= 2ΠΠ(1.1)(1.1)22(59/450)(59/450)= 0.99 cm= 0.99 cm22

MR QuantitationMild Severe

Jet Area (cm2) <4; <20% LA ≥40% LA

VC (cm) <0.3 >0.6

RV (cc/beat) <30 ≥60

RF (%) <30 ≥50

ERO (cm2) <0.2 ≥0.4

Pulm vein flow

Blunted systolic Systolic reversal

LA size N or dilated 1+ Dilated +++

SAM

Outflow Tract Obstruction

Cardiac Tamponade

RA Diastolic CollapseRA Diastolic Collapse

Type A Dissection: TEE

MHMC #0777095

Type A dissection with flap extending to just superior to RCA ostium

Aortic Dissection:

MHMC #0777095

Demonstration of extension of dissection distally

TEE Distal Thoracic Aorta

Diabetes + Hyperglycemia

neuro injury after focal + global ischemia myocardial infarct size WBC function

• Impaired wound healing risk infection, especially gluc > 250

Reasons for Hyperglycemia

1. insulin requirements w obesity, steroids, stress response to surgery + CPB

2. Excess glucose in pump prime, cardioplegia

3. gluconeogenesis + glycogen breakdown (CPB + stress response)

4. glucose utilization: hypothermia

5. insulin production: pancreatic hypoperfusion

Smith et al: J Cardiothorac Vasc Anesth 2005;19:201

Portland Protocol: Starr Center for Cardiac Surgery. www.starwood.com/research/insulin.html

Diabetes + Deep Sternal Wound Infection

• Hyperglycemia - major role in impaired wound healing + deep sternal wound infection

• Insulin infusion + moderate control – Titrate infusion to gluc 125-175 mg/dl– Start in OR, continue to POD 3

incidence to 0.3%, similar to non-diabetics

N Engl J Med 2001;345:1359-67

Van Den Berge Study

• RCT, 1548 diabetic + non-diabetic SICU patients– 60% had cardiac surgery

• Compared tight vs. conventional glucose control– Tight: 80-110 mg/dl– Conventional: insulin only if glucose > 210; endpoint

180-200

mortality in tight group 4.6 v. 8% infections, dialysis dependent RF, # transfusions

required, need for prolonged mechanical ventilation

How Tight Should Intraop Control Be?

• Furnary- 99: < 200 w insulin infusion ↓ mortality • Van den Berghe- 01: 80-110 w insulin infusion ↓

mortality (vs 180-220)• Furnary- 03: < 150 w insulin infusion ↓ mortality

(vs > 250)• Finney- 03: < 145 • Lazar- 04: < 200 w insulin infusion (vs > 250)• Ouattata- 05: < 200 w insulin infusion

MHMC Study

• Prospective, non-randomized, n=40• Diabetics received continuous infusion regular

insulin, 10 u/m2/h + variable D10W, starting rate 100 ml/h or 9.4 gm gluc/h

• Target glucose 101- 140• Standardized anesthetic, bypass, cardioplegia• POC glucose testing + multiple biochemical

measurements

J Cardiothorac Vasc Anesth 2005;19:201

MHMC Study- Results

• 53% achieved adequate intraop control + 35% had control by end of surgery [total =88%]

• 12% never had control (starting glucose 307-550)

• 25% had hypoglycemia requiring D50 (mean gluc 57, range 33-74, mostly CRF pts)

J Cardiothorac Vasc Anesth 2005;19:201

Smith et al: J Cardiothorac Vasc Anesth 2005;19:201

Current Approach- Diabetics

• Insulin infusion- mix 250 units regular insulin in 250 ml 0.9% saline

• Flush line w 25 ml [insulin binds to tubing]• Starting dose: gluc/100 per hr, continue in ICU• Target glucose 100 - 150• Measure gluc q 1h• Bolus doses can be given IV• Be careful with renal failure +after CPB-

accumulation of insulin + risk hypoglycemia

Cognitive Dysfunction

• Inability to perform normal activities after surgery

• 4 major domains of function1. Verbal memory + language comprehension2. Abstraction, visuo-spatial orientation3. Attention, psychomotor processing speed,

concentration4. Visual memory

Newman MF: SCA Annual Meeting, 2007

Newman MF: N Engl J Med 2001;344:395. Duke, n=261

Cognitive Decline, CABG

0

25

50

75

Discharge 6 weeks 6 months 5 years

%

Social + Economic Costs

• Cognitive dysfunction– ↓ quality of life– ↓ return to work– Altered personality, relationships – ↓ sexual function

Implications• Abrupt decline in cognitive function

heralds:– Loss of independence

– Withdrawal from society

– Death

Seattle Longitudinal Study of AgingBerlin Aging Study

Potential Mechanisms1. High-risk patients2. High-risk surgical procedures3. High-risk anesthetic techniques

Patient Risk Factors

• Predictors: ↓ baseline cognition, deficit at discharge, ↑ age, ↓ yrs of education

• Not predictive: EF, HTN, DM, surgical factors: XC time, CPB time

• Etiology: ASVD of proximal aorta, genetics, anesthetics, pre-existing brain disease

Newman MF: SCA Annual Meeting, 2007

Genetic Factors

• ApolipoproteinE ε-4 hyp: APOE allele- ↓ cognitive outcome

• Single nucleotide polymorphisms: SNPs- modulate inflammation, cell matrix adhesion/interaction, lipid metabolism, vascular reactivity, PEGASUS study:– minor alleles of CRP 1059G/C + SELP

1087G/A associated w POCD

Newman MF: SCA Annual Meeting, 2007

Surgical Factors: Aortic Manipulation

Emboli detected by TEE after unclamping; Barbut D: 1996

Microemboli or SCADs

• Small capillary + arteriolar dilations: 10-70 microns

• “Footprint” of embolic material during CPB– density correlates with

CPB duration after CPB, most gone

by 1 wk

Moody DM: AnnThorac Surg 1995;59:1304

Anesthetic Factors

• May interact w peptides- ↑ oligomerization, amyloid deposition + protein folding

• Low BIS levels were associated w ↑ risk in elderly [cumulative hr BIS < 45]

• Longitudinal studies in progress to assess POCD, delirium + effect of anesthetics

Monk TG: Anesthesiology 2004;A62Newman MF: SCA Annual Meeting, 2007

Hyperthermia + POCD

Anesthetic Risk Factors

• Anesthetic agents affect release of CNS neurotransmitters– acetylcholine, dopamine, norepinephrine

• Effects of anesthetics on cholinergic neurons in the basal forebrain [memory regulation]?

• Effects of aging on choline reserves• Difficult to evaluate effects of anesthesia on long

term memory + cognition

Blood Trx + Blood Conservation

• Cardiac surgery consumes >80% blood products transfused at operation

• Blood products may be assoc w major morbidity + mortality: TRIM, TRALI, infection, death

• Trx practices vary greatly• High risk pts: Elderly, Preop anemia / coagulation

defect, Preop antiplatelet drugs, Redo or complex procedure, Emergency, co-morbidities

Optimal hematocrit-1

• Therapeutic dilemma: Anemia is bad, but so is transfusion

• Anemia– ↑ mortality– ↓ quality of life– Jeopardizes organ viability, especially in

presence of limited vasodilator reserve

Gravlee GP. SCA Annual Meeting, 2007

Optimal hematocrit- 2

• Therapeutic dilemma, cont’d

• Transfusion is bad– ↑ mortality + morbidity – immediate ↑ O2 transport is limited– TRIM, ↑ inflammation [role of leukoreduction],

TRALI– Viral/bacteria/parasites

Gravlee GP. SCA Annual Meeting, 2007

Transfusion Avoidance Techniques

• High yield: – ↑ preop Hct

– ↓ CPB priming volume

– RAP: retrograde autologous priming

– Effective intraop cell saver

– Ultrafiltration

• Lower yield: – Antifibrinolytics

– Protamine dosing

Gravlee GP. SCA Annual Meeting, 2007

Retrograde Autologous Priming

• Replace crystalloid prime w pts own blood

• Limits degree of HD

• Fewer pts reach critical trx trigger

Murphy GS. SCA Annual Meeting, 2007

Retrograde Autologous Priming- 2

• How to do this?– Heparinize, place arterial cannula, allow pts

blood to flow backwards + displace crystalloid [perfusionist: “rapping”]

– Maintain SBP > 100 using small doses of PHE (80-400 ug). Turn off vasodilators

– Primary risk- hypotension

Murphy GS. SCA Annual Meeting, 2007

Retrograde Autologous Priming-3

• What is the data?1. Rosengart, 98: ↑ Hct, ↓ RBC trx

2. Shapira, 98: ↑ Hct, ↓ RBC trx

3. Balachandran, 02: ↑ Hct, ↓ RBC trx

4. Eising, 03: ↑ COP, ↓ extravascular lung water+ earlier time to mobilization

5. Murphy, 04 + 06: ↑ Hct, trend to ↓ mortality, delirium, afib, + vent > 24 hr

Cell Salvage- 1• After bypass: transfer blood from prime to cell

saver bowl for washing• Can also collect shed blood for washing• Hct of processed blood: 60%, 2-3 DPG but

processing eliminates platelets +factors• Savings: ~ 1-2 units allogeneic blood

Cell Salvage- 2

• Requirements: CPB– Anticoagulated blood

– Centrifuge bowl + tubing

• Shed Blood– Aspiration assembly

– Reservoir

– Tubing

Cell Salvage- 3 – Few disadvantages in heart room because have:– Dedicated perfusionist + heparinized pump

prime and– Wound is clean– Risks:– Air embolism w infusion under pressure– DIC if use “cell saver suction” for

thrombogenic material

Ultrafiltration

• Remove water + low MW substances under a hydrostatic pressure gradient

• Induces hemoconcentration: ↓ total body water accumulation + inflammatory mediators

• ↓ bleeding, blood trx, morbidity + mortality

• Initially validated in peds, but also adults

Tassani 99; Kiziltepe 01; Leyh 01; Luciani 01;

Reasons Why Trx Avoidance Techniques Fail

• Had PVCs, PACS

• Had to start vasopressors/ inotropes

• Looked a little oozy

• BP a little low

• CI was a little low

• Pt was old

• Pt was high risk

Gravlee GP. SCA Annual Meeting, 2007

Summary

1. IOTEE: routinely use for valves, often helpful for CABG

2. Hyperglycemia: treated w insulin infusion, target glucose < 150, especially if diabetic

3. Cognitive dysfunction: high risk pts + surgery; genetics + anesthetic factors play a role

4. Multimodal blood conservation techniques work well: RAP, cell saver, ultrafiltration, amicar, protamine dosing